A new carbazole alkaloid, siamenol (1), and two known alkaloids, mahanimbine (2) and mahanimbilol (3), have been isolated from the organic extract of Murraya siamensis. The novel compound exhibited HIV-inhibitory activity.

Three new isomalabaricane triterpenes, 29-hydroxystelliferin E (1), 29-hydroxystelliferin A (2), and stelliferin G (3), together with the known triterpene 3-epi-29-hydroxystelliferin E (4), were isolated from the organic extract of the sponge Jaspis sp. collected in the South Pacific. All the compounds isolated showed antiproliferative activity against melanoma cells (MALME-3M).

Four new indoles, ancorinolates A-C and bis-ancorinolate B, which contain sulfamate and sulfate groups, were isolated from the aqueous extract of the sponge Ancorina sp. In addition, ancorinazole, an indolo[3,2-a]carbazole also possessing sulfamate and sulfate groups, was isolated from two separate New Zealand collections of Ancorina sp. Ancorinazole is the first indolo[3,2-a]carbazole described as a natural product. Ancorinolates A (1) and C (3) showed weak HIV-inhibitory activity in the XTT-based, anticytopathicity assay.

Six flavonoids, among them a new dihydroflavonol, 6,8-diprenylaromadendrin (1), and the flavonol 6,8-diprenylkaempferol (3), have been isolated from the organic extract of Monotes africanus. The isolated compounds containing a 5,7-dihydroxy-6,8-diprenyl system in the A ring of the flavonoid (1, 3, and 6) exhibited HIV-inhibitory activity in the XTT-based, whole-cell screen. In addition, several (13)C NMR assignments of lonchocarpol A (6) were corrected.

Monanchorin, a guanidine alkaloid with an unusual bicyclic skeleton, together with the known pentacyclic alkaloid crambescidin acid have been isolated from the aqueous extract of the sponge Monanchoraungiculata.

No abstract

No abstract

Using a high throughput screen based on the interaction of the HIV-1 gp41 ectodomain with the virucidal protein cyanovirin-N (CV-N), we isolated two new peptides which inhibited the binding of CV-N to gp41 and which subsequently showed anti-HIV activity in a whole cell assay. A 5-kDa (contrajervin) and 10 kDa (treculavirin) peptide were isolated from Dorstenia contrajerva and Treculia obovoidea, respectively. Treculavirin was composed of two subunits, each containing 50 amino acid residues, which are covalently linked by at least one disulfide bond between the subunits. Both peptides were shown to bind to gp41 and gp120 and to inhibit the cytopathic effects of HIV-1 RF infection in a human T-lymphoblastoid cell line (CEM-SS).